TABLE 1

Bacterial species associated with colon cancera

Name(s)RelationshipReference(s)
Citrobacter rodentium Min mice inoculated with this species had a 4-fold increase in colonic tumors. Found only in mice. 25
Enterococcus faecalis Produces superoxide and hydrogen peroxide, both of which can damage DNA in epithelial cells 26, 27
Clostridium cluster XVIa (Clostridium scindens, C. hiranonis, and C. hylemonae) and Clostridium cluster XI (C. sordellii)Can produce secondary bile acids, such as deoxycholic acid (DOC), that increase tumor burden in wild-type male B6.129PF2/J mice 28, 29
Acidovorax speciesAssociated with increased risk for colon cancer and may act as a pathogen by increased metabolism of nitroaromatic compounds 30
Enterotoxigenic Bacteroides fragilisProduces a toxin that caused colitis and tumors in multiple intestinal neoplasia (MinApc716+/−) mice through an IL-17-dependent pathway 31
Streptococcus gallolyticus Present in approximately 20 to 50% of colon tumors compared to less than 5% of normal tissue in CRC patients. Patients with high counts of S. gallolyticus have increased expression of proinflammatory cytokines, including interleukin-1 (IL-1) and cyclooxygenase-2 (COX-2). 32
Escherichia coli NC101Produces genotoxic colibactin that led to increased tumor burden in AOM/Il10−/− mice 33
Fusobacterium nucleatum Induces hyperproliferation of human colon cancer cell lines through binding of its FadA adhesin to E-cadherin. Also, promotes immune evasion of tumors through binding of its Fap2 adhesin to TIGIT receptors on immune cells. 34, 35, 37, 38
Akkermansia muciniphila Mucin-degrading species were found in 4-fold-larger amounts in CRC colons than in normal colons 36
  • a Species names, details of association, and references are listed in chronological order.